1. Field of the Invention
The present invention relates to a method of manufacturing a member pattern such as a wiring structure, a method of manufacturing an electron source using the method of manufacturing a member pattern and a method of manufacturing an image display device using the method of manufacturing a member pattern.
2. Related Background Art
A method of manufacturing a member pattern in which an insulating film or conductive film is formed in a desired pattern on a substrate is used in a method of manufacturing a wiring structure. The wiring structure, in turn, is applied to an imaging device and an image display device, such as a plasma display panel (PDP), a liquid crystal display element (LCD), an electroluminescence display element (ELD) and an electron-emitting display element. In the following description, an electron-emitting display element will be taken as an example.
Electron-emitting elements have been disclosed in Japanese Patent Application Laid-Open No. 8-321254 and the like. FIG. 3A is a schematic plan view of a surface-conductive electron-emitting element, and FIG. 3B is a schematic cross-sectional view of the element. In FIG. 3, reference numeral 31 denotes a substrate, reference numerals 32 and 33 each denote an electrode, reference numeral 34 denotes a conductive thin film and reference numeral 35 denotes an electron emitting section.
The inventors have studied increasing of the area of an image forming device having a large number of such surface-conductive electron-emitting elements disposed on a substrate. There are many possible methods of fabricating an electron source substrate (wiring device) in which an electron-emitting element and a wiring are formed on a substrate. For example, a printing technique, such as screen printing or offset printing, may be diverted to the fabrication of the surface-conductive electron-emitting element and the electron source substrate including the same. Printing techniques are suited to fabricate a large-area pattern, and forming an electrode of the surface-conductive electron-emitting element by a printing technique allows a large number of surface-conductive electron-emitting elements to be easily fabricated.
In Japanese Patent Application Laid-Open No. 8-34110, there is disclosed a method of using screen printing to form an x-directional wiring extending in the x direction, a y-directional wiring extending in the y direction, and an insulating layer for insulating the x-directional wiring and the y-directional wiring from each other, the wirings being intended for driving each electron-emitting element on a rear plate (substrate). With reference to FIGS. 4 to 8, the method of manufacturing an electron source disclosed in this Japanese Patent Application Laid-Open No. 8-34110 will be now described.
First, plural pairs of electrodes 42, 43 are arranged on a substrate 41 (FIG. 4).
Then, a conductive paste is applied to the substrate by screen printing and baked, thereby forming a wiring (y-directional wiring) 44 that interconnects the electrodes 43 (FIG. 5).
Then, an insulating paste is applied to the substrate by screen printing and baked, thereby forming an insulating layer 45 that insulates a wiring (x-directional wiring) 46 described later and the wiring 44 from each other (FIG. 6).
Then, a conductive paste is applied to the substrate by screen printing and baked, thereby forming the wiring (x-directional wiring) 46 that interconnects the electrodes 42 (FIG. 7).
Finally, a conductive film 47 that interconnects the electrodes 42 and 43 of each pair is formed (FIG. 8).
According to this method, a thick-film wiring having a low resistance can be readily manufactured with a reduced process time per substrate and at a reduced cost.
Furthermore, in recent PDPs with a large screen and a high definition and displays using electron-emitting elements, printability of finer lines and spaces is required, and therefore, element electrodes, wirings and the like may be totally formed by photolithography.
In forming a large number of electron-emitting elements for display using the photolithography, the conventional NTSC requires hundreds of thousands of electron-emitting elements to be precisely integrated, and the HDTV requires millions of electron-emitting elements to be precisely integrated. In such a case, the wirings 44 and 46 and the interlayer insulating layers 45 are required to be formed with higher reliability.
The interlayer insulating layer is desirably formed thick so that the dielectric constant is not higher than a certain value to keep power consumption and heat generation during driving at a low level. In addition, any pin hole or the like has to be prevented from occurring. Thus, interlayer insulating layers stacked only in a single layer are not enough in many cases. Thus, in order to eliminate defects including pin hole short-circuit at a wiring intersection in a matrix structure having millions of wiring intersections, interlayer insulating layers may be stacked in two or more layers. However, even in such a structure having the insulating layers stacked in multiple layers, short-circuit sometimes occurs at an intersection between an x-directional wiring and a y-directional wiring.